Figure 5: The mTORC1 signaling pathway plays an important role in the upregulation of PPARγ expression by RA. (a) Differentiated 3T3-L1 cells were cultured with 0, 1, 2, and 4 mg/mL RA for 48 hours. Cell extracts were then subjected to western blot analysis with antibodies specific for total and phosphorylated p70S6K (Thr389), PPARγ, and β-actin. (b) Differentiated 3T3-L1 cells were cultured with rapamycin (0 or 30 nM) and RA (0 or 2 mg/mL) for 2 or 48 hours. Cell extracts were then subjected to western blot analysis with antibodies specific for total and phosphorylated p70S6K (Thr389), PPARγ, TNFα, and β-actin.